Nautiloid Cephalopod?

[BenK]

Is this a fragment of a nautiloid cephalopod? It is quite large. Found in a limestone quarry. Thanks!

[BenK]

[MeargleSchmeargl]

What is the formation the quarry delves into? Location of the finds? This looks more like orthoceras than anything.

[Fossildude19]

Orthocone cephalopod. Probably not Orthoceras. 

 

 

 

Where (County, state?) was this found? 

 

 

 

[BenK]

Eastern Missouri. Maybe Kimmswick formation but will have to clarify that.

[Fossildude19]

Eastern Missouri covers a big area.    

 

Check this geologic map to see what age the sediments may be. 

 

[MeargleSchmeargl]

10 minutes ago, Fossildude19 said:

Orthocone cephalopod. Probably not Orthoceras. 

 

 

 

Where (County, state?) was this found? 

 

 

 

Orthocone, Orthoceras, what's the difference? 

 

[Fossildude19]

5 minutes ago, MeargleSchmeargl said:

Orthocone, Orthoceras, what's the difference? 

 

Click the Blue link.  

[BenK]

It is 100 percent Ordovician I'll say that much. 

 

I own some land in Ste. Gen county that is right on the Ordo/Miss line so I find some decent things there from time to time. 

[MeargleSchmeargl]

5 minutes ago, Fossildude19 said:

Click the Blue link.  

Oh, so there was a naming change when they looked at Orthoceras and body structures of other orthocones, and they had differences in things like the siphuncle. Orthoceras itself is a genus, rather than being a unifying group.

 

Duly noted!

[Rockwood]

11 minutes ago, MeargleSchmeargl said:

like the siphuncle.

Any angle show evidence ?

The top might be the best bet. 

[BenK]

Thanks for all your information everyone! I see this is a very helpful site already. I will get some top pics posted this evening.

[doushantuo]

"orthocone" is a sort of shorthand morphological descriptor.

(greek for "straight cone")

 

as regards siphuncular structures:a recent baseline

 

[Tidgy's Dad]

Quite a nice orthocone piece